Staff scheduling and rotas

Key providers need to continue to provide services to their service users. However, these services are impacted by two factors:

  • measures to reduce the spread of the virus, for example isolation and social distancing; and
  • changes to the service users qualifying to access the service, for example only children with key worker parents can access schools.

Where the second factor leads to a reduction in demand for services, the provider must consider how the services can be staffed.

Unlike many office-based workers, many front-line service staff – teachers, care workers, community support etc. – cannot work from home. In cases where staff must be out in the community, the question then becomes what – if anything – can be done with the scheduling to reduce risks?

For example, consider teachers in a school with a significantly reduced cohort of children of key workers or with other qualifying special needs. Schools, especially primary schools, are particularly interesting to consider as daily routines and behaviours make maintaining ‘social distance’ more difficult – as has been seen anecdotally on social media, teachers are not making young children stay 2m away when they are upset or anxious.

Given the demographic of this cohort, it is likely that the existing staffing will be more than double that required on any individual day, even after accounting for staff self-isolation needs. This means that on each day more than half of the staff can remain at home and less than half can come in to school.

Let us assume that the staff can be split into two groups (A and B), each group comprising the range of competencies to operate the school with the reduced cohort of children (C).

One intuitive rota scheme would be ‘day-on-day-off’. In this scheme, on the first day, staff group A would be in school with the children (C) and staff group B would remain at home. On the following day, staff group A would stay home while staff group B would be in school with the children.. This pattern would repeat, and is illustrated over a two week period in figure 1, below.

Day-on-day-off rota scheme where staff groups A and B come into school on alternate days

Figure 1. ‘Day-on-day-off’ rota scheme where staff groups A and B come into school on alternate days

This scheme would, in normal circumstances, meet the basic scheduling requirements: the children are receiving appropriate education and care, and staff perceive the rota as fair.

However, is it the best rota in our current context?

Public Health England state that “infections spread easily in closed spaces where people gather together [guidance on social distancing]. We can therefore assume that there is a significant risk of transmission amongst the people (staff and children) in school each day. This is illustrated by the red arrows in figure 2.

Day-on-day-off rota showing transmission risk.

Figure 2:. ‘Day-on-day-off’ rota showing transmission risk.

Whilst there are no cases of Covid-19 in any of the groups A, B and C there is clearly no risk of transmission.

However, consider one person in any of these groups becoming infected with the virus. If this was a child, then there is a risk of transmission to other children and either group A or group B staff on the first day, and to other children and the other group of staff on the second day. If this was a member of staff, then similarly on the first day there is a risk of transmission to other staff in their group and to the children.

Given what we know about the pathology of Covid-19, it may easily take a couple of days before someone who has contracted the disease realizes and self-isolates. Although the current science suggests that how contagious someone is relates to how severe their symptoms are, this nonetheless introduces a risk of spread.

The pathology also suggests that there is on average 5.2 day incubation period [journal of autoimmunity: epidemiology and pathogenesis of coronavirus disease outbreak- Hussin A. Rothan, Siddappa N. Byrareddy]. So once transmission has occurred, we can expect symptoms to take a few days to appear, and for the newly infected person to themselves become contagious.

With the day-on-day-off rota, it is very likely that a single case in a child would cause exposure to all three groups A, B and C within a couple of days. Good hygiene will reduce the risk of actual transmission, but at this point, everyone is at risk.

Consider this alternative rota: week-on-week-off, where staff group A staff the school for the first week, and staff group B for the second. This is illustrated in figure 3, below.

Week-on-week-off rota showing transmission risk

Figure 3. ‘Week-on-week-off’ rota showing transmission risk.

In this rota, during each week one staff group is effectively isolated. Transmission during each week can only occur among the children C and one of the staff groups (B in the first week shown, and A in the second).

This means:

  • in each week, one staff group is not at risk of contracting the virus as they are at home
  • given the average incubation period of 5.2 days, anyone infected during one week will likely not become contagious themselves until the following week – if this is a member of staff, this will be during their ‘at home week’, and therefore gives them the opportunity to self-isolate with no risk of onward transmission to other staff in either group A or B, or the children.
  • a child who contracts the virus and begins to show symptoms is only at risk of infecting other children and one of the two staff groups.

There are several assumptions built in to this simple example, including assuming there are no intra-group transmission risks outside the school, and that people contracting the virus will be symptomatic (which is not always the case).

However, we can see that it is likely that a week-on-week-off rota is likely to prove more robust than a day-on-day-off rota.

The scenario described here is specific to a school where distinct groups of staff are in contact with a single group of children. This has transmission characteristics that are different, for example, to those in an office.

Many corporations have introduced split-team rotas for staff who cannot work from home, where each team separates in to two who have a similar alternating rota to avoid any risk of spread between the two groups.

In these cases, the transmission risk of person-to-person is removed, but there is a risk of transmission via surfaces. There is still some uncertainty but most experts agree that the virus will survive longest outside of the body when on a hard surface at stable temperature with no direct sunlight. Does that sound like an office to you? In these circumstances estimates of virus viability vary from 36 to 48 hours.

This can of course be mitigated by daily cleaning, but once again, the week-on-week-off schedule that leaves the office empty at weekends gives from close of business on Friday until the office opens on Monday morning for any residual virus on office surfaces to die.

Chris Lees

About Chris Lees

Mathematician, Workplace Strategist, Occupancy Analyst, Endurance Running Coach, Dementia Charity Trustee, Young People's Mental Health Parent Advisor and Entrepreneur.

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